The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component that can be created using a fabrication process) has decreased. As lithographic features are reduced to below 40 nm, high numerical aperture processes are needed to overcome the resolution limit. The use of a trilayer films scheme appears to be promising in this regard.
In a trilayer films scheme, a photoacid generator (PAG) may be blended with components in a middle layer. When the middle layer is exposed to radiation, the PAG generates acid. Due to the porous nature of the middle layer, this acid can diffuse from the middle layer to a photoresist layer, which reduces resist contrast. Thus, a process and material that minimizes or removes these problems is desired.